New Research On Tropical Corn Could Help Reduce Fertilizer Used By Farmers

Researchers at the University of Wisconsin-Madison have helped discover a corn variety that could reduce the amount of nitrogen fertilizer farmers need to spread.

The tropical variety of corn has been grown in Oaxaca, Mexico for thousands of years. Because the area’s soils have little nitrogen, the corn has adapted over the years, developing a system for taking nitrogen out of the air.

This process, called nitrogen fixation, is something researchers around the world have been working to identify and breed into corn for more than 100 years.

Jean-Michel Ané, a professor of bacteriology and agronomy at UW-Madison, said he couldn’t believe it when a researcher from food company Mars, Inc. approached him about the possibility.

“I was extremely skeptical because that is very unusual,” Ané said. “The only plants that really do that nitrogen fixation with bacteria are mostly legumes, like soybeans.”

Because the idea was so revolutionary, Ané said he and his partners took almost 10 years to verify what was happening. Their study was recently published in the journal PLOS Biology.

“We wanted to be very careful in our claims that nitrogen fixation is taking place in that corn so we used absolutely all of the techniques,” Ané said.

The team found that roots along the stalk secrete a sugary gel for bacteria, which turns atmospheric nitrogen into a form usable by the plant. The corn can get up to 80 percent of its nitrogen through the process, which would have huge impacts if the trait could be bred into U.S. corn varieties.

“We would hope to use less fertilizer on that kind of corn. So we need to evaluate more precisely, OK, how much less? How much can we save in terms of fertilizer? What’s the impact in terms of environment?” Ané said.

Using less artificial fertilizers would save farmers money and reduce the potential for nutrient runoff into local waterways. Ané said the trait could also help farmers produce corn in developing countries where fertilizers are more expensive.

“At least five years of breeding are necessary and easily another five years will be necessary to understand the value of that corn,” Ané said.

Ané said he hopes the finding will prompt researchers to look for inspiration in indigenous forms of other crops.

“There is value in looking at what nature has developed already and in particular when it comes to crops, to look at these landraces or sort of progenitors of our crops that contain so much diversity and so much genetic potential,” Ané said. “Obviously, nature found a way to develop a system that we didn’t even think of.”